To embroider a pattern on a tubular workpiece it is necessary to fit it to a normally tubular frame that is in turn fitted to a free arm or bed of an embroidery machine. Then as described in U.S. Pat. No. 4,653,415 of Tajima and U.S. Pat. No. 4,665,844 of Shibata longitudinal movement, which here is intended to cover movement parallel to the center axis of the tubular frame, is imparted to the entire frame and its supporting mechanism and transverse movement is effected by rotating the tubular frame on the free arm about its axis. Such a system allows a transfer mechanism or pantograph to accurately guide the workpiece relative to the stationary stitching station so that the desired design can be stitched into the goods.
Such an arrangement is highly effective for small areas of embroidery, but is limited by the size of the window provided in the tubular support frame. In addition for longitudinal movement the entire support structure must be moved along with the frame so that the necessary drive must be able to accurately displace a considerable mass. For transverse movement a fairly complex system of interengaging structure on the frame and on the free arm must be moved to rotate the frame. Hence the drive must be made fairly powerful and must operate fairly slowly to obtain the necessary accuracy. What is more such machines can normally only accommodate a single size of frame so that workpieces of different sizes cannot be accommodated conveniently.